Although, by definition, vitamins required by man cannot be
synthesized within the tissues, it is important to note that bacteria
within the gut can synthesis many of the vitamins required by man. The
human intestinal bacteria can synthesize vitamin K, a member of the
naphtoquinone family.
Vitamin K2 also called
menaquinone also is a product of metabolism of most bacteria including
the normal intestinal bacteria of most higher animal species. The
vitamin K bacterial reactions occur, in part, in the ileum, where the
menaquinone is absorbed.
Among bacteria involve in synthesizing vitamin K are: Bacteroides spp., Eg. Lenta, Propionibacterium spp., Veillonella spp., staphylococci, enterococci enterobacteria.
Most
of the vitamin B12 (cyanocobalamin) required by humans comes indirectly
from the meat and milk of ruminants. The synthesis of B12 is ruminant
is exclusively bacterial origin. It appears most of the bacterially
formed B12 I human occurs in the large bowel. It was demonstrated that
E. coli, Bifidobacterium spp., Veillonella spp., Fusobacterium spp., Eurobacterium spp., and Clostridium spp., among the bacteria that synthesized B12 in the small intestine.
Folic
acid and thiamine B complex vitamins are also synthesized by bacteria
in the intestinal tract. Other vitamins synthesized by intestinal
bacteria are:
*Biotin
*Folic acid (B2)
*Pantothenic acid (B5)
*Niacin (B3)
*(Pyridoxine) B6
Vitamins synthesis by intestinal bacteria
